Pros:Very good looking and sounding pipe. Much lighter than stock, and narrower. Installation was very easy, and the muffler came very well packed/protected.

I haven't tried the additional optional piece that lowers the sound an additional ~3dB, might put that in after the first fiberglass repack. Glad I got this muffler, very happy after 1000 miles!

Cons:None really, except that I'll be needing to repack every 5-6k miles when I do an oil change, but this isn't really a con as I knew this when buying.

M4 GP Slip-On Exhaust for ZX6R 13-15

Outstanding

by Lisa L. on 07/24/15

Pros:This product is amazing! The exhaust made my bike extremely loud, it has a deep sound and it doesn't sound whiney or annoying. It was fairly easy to put on, it took me about 30-45 minutes to install. If you don't like a loud bike, you might want to get the silencer and pay the extra $35.00 (I didn't get one).

Cons:The one con that I noticed was because of the exhaust lines that don't have anywhere to go the FI light flashes. There's a part you can order to fix that, but I still haven't gotten it myself. It's only a nuisance to have it flash while you're riding, especially at night. The bike's sound makes that small hassle worth it all!